Patent GB-430028-A (GB)
Title: Improvements in and connected with fire-extinguishing sprinkler systems
IPC: A62C35/64
Filed: 1933-12-12
Abstract: 430,028. Sprinkler systems. BURGESS, A. F., 10, New Court, Lincoln's Inn, London.- (Automatic Sprinkler Co. of America; 910, Standard Bank Building, Cleveland, Ohio, U.S.A.) Dec. 12, 1933, No. 34957. [Classes 47 (i) and 47 (ii)] Relates to sprinkler systems of the kind in which the main valve is released mechanically by pressure-sensitive devices actuated by the expansion of air in bulbs connected to said devices by a supplemental piping, means being provided for maintaining automatically the requisite pressure in the supplemental piping. The main pipe 24, Fig. 1, communicates with the main valve 26 through a gate valve 25. If the gate valve is partially or wholly closed, its stem 31 opens a valve in a pipe 36, 38 to allow water to pass to a pipe 39 to operate a syren 40 and a diaphragm-actuated electric bell 41, and also closes contacts in the circuit of a bell 43. An auxiliary water supply, operable in case the supply in pipe 24 should fail, is connected to the pipe 36 by pipes 29, 37. The main valve 26 comprises a clapper 47, Fig. 6, normally held closed by a latch 50 pivoted at 51 and having an extension 52 passing through an opening 53 in the valve casing. The distributing pipes 27, 28 normally are dry and charged with air at a certain pressure. A pipe 56 leading from the valve chamber 46 conveys water, when the main valve opens, to actuate a fire gong 55 and an electric bell 41<1>. The syren 40 and gong 55 are housed in a common casing. The latch 50 is turned on its pivot, to release the valve 47 when fire conditions occur, by a weight 64, Fig. 6, normally supported at the upper end of an open housing 63 at the side of a sealed casing 61 which houses an automatic release mechanism adapted to release the weight on either an increase or decrease of the pressure in the supplemental tubing. This release mechanism, which includes an escapement device 81, a manual resetting mechanism, and a diaphragm chamber 68 in communication with the pipings 144 and with a pressure-equalizing vent 76, Fig. 12, is generally similar to that described in Specification 430,027, and is housed in the chamber 60 in which, normally, a pressure similar to that in the pipings 144 is maintained. The main release lever 86 of the mechanism is sealed, where it leaves the chamber 60, by a diaphragm, and engages, at its outer end, a lug 108 on a latch 106 pivoted to the weight 64. The latter is guided on a rod 104 pivoted to the latch extension 52. The latch 106 is weighted at 1061 and has an upstanding finger 109 which normally engages a spring- biassed plunger 110 to prevent rotation of the latch. The weight is released to open the valve 47 when a pressure variation in the diaphragm chamber 68 moves the escapement lever 81, Fig. 12. A manual release for the weight is provided by a pull lever 111 and by a cable 113, which are connected to the plunger 110 so that the latter can be raised to release the latch 106. An alarm is given by an electric bell 57 when the weight drops, through contacts 57<1> normally held open by a finger engaged by the weight. The various pipings 144 are connected to the diaphragm chamber 68 through pressure-controlling units 148, Figs. 6 and 12, housed in the chamber 60. Each unit comprises a chamber 152 connected to the piping 144 and to the chamber 60 through a pressure-equalizing vent 761, a chamber 151 connected to the diaphragm chamber 68 by a pipe 149 and to the chamber 152 by a pipe 153 and mercury seal 154, and a vent pipe 155 with seal 156. The seals are so arranged that an increase of pressure in piping 144 is communicated to chamber 68 but not to chamber 60, and a fall of pressure in the piping, as by fracture thereof, is communicated to chamber 68 while the seal 156 does not allow pressure equalization through the vent pipe 155. Similarly, the seals prevent pressure changes, in one unit 148 from being weakened by losses to other units 148. Abnormal pressure rises in the piping 144, which might injure the apparatus, are vented by pipe 155. In use, a certain pressure is applied to the chamber 60, and is equalized throughout the piping system through the vents 76, 76<1>, which subsequently allow pressure-equalization for normal temperature variations. However, a sudden rise of pressure in the piping 144, due to fire, or fall, due to fracture, is applied directly to the diaphragm chamber 68, so that the diaphragm 66 is flexed inwardly or outwardly, producing release of the weight 64. The expansion bulbs 146 in the piping 144 each comprise a sealed casing 158, Fig. 3, suspended from a bracket 159 by a cage 160. A vent 166 in the casing is sealed by a fusible washer. If the temperature rises slowly to a predetermined point, the washer fuses, releasing the pressure in the piping 144. At the same time, a coloured tube 169 is released to hang down and indicate that the fusible release has functioned. The pipings 144 are supported on the sprinkler pipes 28 in a readily accessible position by clamps and wedges, and are protected adjacent the sprinkler heads 178 by cupped guards 181. A predetermined pressure is maintained automatically in the sprinkler and supplementary pipes by an air injector 184, Fig. 1, which discharges air into the sprinkler pipes by a pipe 216 and into the chamber 60 through a drier and filter 220 and pipe 221, 222. The injector, Fig. 15, is float-operated, and comprises a casing providing a float chamber 185 and a water chamber 186 with overflow 189. A dual valve arrangement has an air inlet 209, and an injector supplied with water from the main pipe 24 by a pipe 207. The valves are controlled by a float 190 on a rod 192, the position of the float being controlled by the pressure existing in the piping systems. If the pressure in the systems falls, the float rises, say to the line b. The rod 192 then opens the injector valve 204, so that water with indrawn air is forced into the chamber 185. The air separates, and passes into the piping systems until the pressure is restored and the float is forced down to close the valve 204 If the injector fails to restore the pressure, the float rises further, say to the line c, and opens a valve 205, allowing water to pass, by the pipe 212, to operate the syren 40. The valves 204, 205 are actuated by sectors 199 which are moved by weights E, A, independently operable by pins on a quadrant 198 linked to the rod 192. The drier, Fig. 16, comprises concentric casings 224, 228, 232 defining a sinuous path 230, 231 for the wet air, the inner casing 232 being packed with a dessicant 236. The chamber 185 of the injector is provided with a restricted vent 245 to atmosphere. This causes a slow fall in pressure in the piping systems and consequently a periodic operation of the injector.